A 5.5 year old boy with total tooth decay (dental caries) is recommended to visit the dentist of a specialized dental hospital in a timely manner. A comprehensive and detailed examination of the mouth and teeth, and then according to the doctor’s guidance and recommendations for detailed treatment. When tooth decay occurs, you can usually go to the dentist for an examination to determine the treatment method. 5.5 year olds with full mouth cavities are commonly treated with fluoride, filling treatment, and preformed crowns. 1. Fluoride: For shallow caries that occurs in a wide range of areas, it can stop the caries from continuing to develop, but it does not restore the shape of the tooth. However, it does not restore the shape of the tooth. 2. Filling: Treatment involves removing decayed tooth tissue, preparing a cavity, and then filling it to restore the shape of the tooth. Deeper cavities require filling with a pulp guard. 3. Pre-crowning: After caries treatment, a crown is placed on the baby tooth to ensure its strength. 4. Root canal treatment: If pulpitis has already occurred, root canal treatment should be performed, i.e., killing the nerve and then filling the root canal. Parents should help their children to be more careful and eliminate their continued consumption of sweets. Supervise the child to pay attention to maintain good oral and dental hygiene, morning and evening brushing, drink less drinks, and after brushing at night can not eat or drink again, to develop a good living and eating habits.